Conventionally, glass flake fillers are used in a wide range of applications. For example, a glass flake filler is mixed in a resin as a reinforcing material. As a specific example, if glass flakes are mixed in a thermoplastic resin, a resin molded product having high strength and good dimensional stability can be obtained.
For example, JP 06 (1994)-9791 A discloses a resin composition obtained by mixing a glass flake filler in a thermoplastic resin. This glass flake filler is composed of glass flakes having an average particle diameter of 10 μm to 2000 μm and an average thickness of 0.8 μm to 1.4 μm, and the glass flakes include glass flakes having a thickness of 0.3 μm to 3.0 μm in an amount of at least 90% by mass. JP 2003-82260 A also discloses a resin composition obtained by granulating glass flakes having an average thickness of 0.5 μm to 20 μm and mixing the granular glass flakes in a thermoplastic resin. The reinforcing effect of the glass flakes included in these resin compositions achieves a high tensile strength and flexural strength of the resin molded products produced using the resin compositions. Furthermore, because of their low shrinkage at the time of being molded (hereinafter referred to as “molding shrinkage”), resin molded products that have excellent dimensional stability can be produced from these resin compositions.
However, since the above-mentioned conventional resin compositions may be unsatisfactory in strength and molding shrinkage for some application purposes, a resin composition capable of achieving a much higher strength and a much lower molding shrinkage is required.